Underlying impacts of invasive cats on islands: Not only a question of predation

Biodiversity and Conservation (Impact Factor: 2.37). 02/2014; 23(2). DOI: 10.1007/s10531-013-0603-4


The domestic cat has been introduced on most islands worldwide, where it has established feral populations and is currently known to be one of the worst invasive mammalian predators. Predation is the strongest deleterious effect of cats on wildlife, inducing a direct negative impact on population size and dynamics, breeding success and changes in species assemblages. Direct predation is not the only damaging impact on native wildlife, since cats can be responsible for other poorly-documented underlying ecological impacts, like competition, hybridization, disease transmission, ecological process alteration, and behavioral change. Here, we pinpoint relevant examples of these ecological impacts, by searching for accurate data from published literature. We used electronic databases covering most of the world islands where the effects of cats were documented. Knowledge of these impacts can be of great importance to preserve insular ecosystem functions and persistence of endangered native species. We emphasize that direct predation processes should not be the only factor considered in the management of invasive cats on islands.

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Available from: Felix Manuel Medina, Dec 26, 2013
    • "Globally, many in situ conservation and reintroduction programs for small predator-vulnerable species are thwarted by predation, competition or disease transmission from feral domestic cats (Felis catus) (Medina et al. 2011Medina et al. , 2014 Nogales et al. 2013;), despite, in many cases, intensive introduced predator control being used (Morris et al. 2004; Moseby et al. 2011b; Wayne et al. 2015). Feral cat predation is considered the single most significant threat to Australian mammals (Frank et al. 2014; Woinarski et al. 2015), yet contemporary feral cat control techniques are inadequate (Dickman 2014; Marlow et al. 2015). "

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    • "Feral cats utilize the 'wild' end of a highly adaptive behavioural spectrum that equips them as destructive predators and disease vectors , with more subtle ecological impacts now becoming apparent (e.g. Medina et al., 2014). The ability of cats to survive either with or without dependency on humans seems intrinsic to their historical value as commensal or companion animals but is also a serious downside to their introduction, intentional or not, to naive ecosystems. "

    Full-text · Dataset · Dec 2015
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    • "Feral cats are acknowledged as one of the world's worst 100 invasive species (Lowe et al. 2000) and are thought to have been an important contributing factor to at least 14% of bird, reptile and mammal extinctions globally (Medina et al. 2011) and at least 16 mammal extinctions in Australia (Johnson 2006). Predation by feral cats can jeopardise conservation programs aiming to reintroduce native fauna into areas of their former range (Moseby et al. 2011; Potts et al. 2012), and cats can have non-lethal impacts on susceptible populations through competition, disease transmission, induced predator-avoidance behaviour and hybridisation (Daniels et al. 2001; Medina et al. 2014). Reducing the impacts of feral cats "
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    ABSTRACT: Feral cats (Felis catus) have a wide global distribution and cause significant damage to native fauna. Reducing their impacts requires an understanding of how they use habitat and which parts of the landscape should be the focus of management. We reviewed 27 experimental and observational studies conducted around the world over the last 35 years that aimed to examine habitat use by feral and unowned cats. Our aims were to: (1) summarise the current body of literature on habitat use by feral cats, in the context of existing ecological theory (i.e. habitat selection, foraging theory); (2) develop testable hypotheses to help fill important knowledge gaps in the current body of knowledge on this topic; and (3) build a conceptual framework that will guide the activities of researchers and managers in reducing feral cat impacts. We found that feral cats exploit a diverse range of habitats including arid deserts, shrublands and grasslands, fragmented agricultural landscapes, urban areas, glacial valleys, equatorial to sub-Antarctic islands and a range of forest and woodland types. Factors invoked to explain cat habitat use included prey availability, predation/competition, shelter availability and human resource subsidies, but the strength of evidence used to support these assertions was low, with most studies being observational or correlative. We therefore provide a list of key directions that will assist conservation managers and researchers in better understanding and ameliorating the impact of feral cats at a scale appropriate for useful management and research. Future studies will benefit from employing an experimental approach and collecting data on the relative abundance and activity of prey and other predators. This might include landscape-scale experiments where the densities of predators, prey or competitors are manipulated and then the response in cat habitat use is measured. Effective management of feral cat populations could target high-use areas, such as linear features and structurally complex habitat. Since our review shows often-divergent outcomes in the use of the same habitat components and vegetation types worldwide, local knowledge and active monitoring of management actions is essential when deciding on control programs.
    Full-text · Article · Jan 2015 · Wildlife Research
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